Plasma delamination apparatus and plasma delamination method

Abstract

This invention provides a plasma delamination method for removing DLC ​​films from the surface of molds, tools, machine parts, or jigs using plasma. [Solution] One aspect of the present invention is a plasma peeling method in which a mold 51, tool, machine part, or jig having a DLC film attached to its surface is placed on the carbon sheet 22 of a first electrode 21 on which a carbon sheet 22 is arranged on its surface, a second electrode 23 positioned opposite the first electrode 21 is connected to earth in an atmosphere of inert gas and oxygen gas or H2O gas, plasma generation power is applied to the first electrode 21 to generate plasma on the surface of the mold 51, tool, machine part, or jig, and the DLC film is peeled off from the surface of the mold 51, tool, machine part, or jig using the plasma.

Description

[Technical Field]

[0001] The present invention relates to a plasma peeling apparatus and a plasma peeling method. [Background technology]

[0002] Applying a DLC (Diamond-Like Carbon) film to the surface of molds, tools, machine parts, or jigs can extend their lifespan compared to molds, etc., that do not have a DLC film applied. Therefore, molds, etc., with a DLC film applied to their surface are often used.

[0003] Even with the use of such molds, the DLC film gradually deteriorates. Therefore, after a certain number of uses, the DLC film on the mold is stripped off, and a new DLC film is deposited on its surface. In this way, the molds are reused repeatedly.

[0004] As a method for removing the DLC film from used molds, etc., the molds, etc. are immersed in a bath containing hydrofluoric acid, thereby removing the DLC film from the surface of the molds, etc., by the hydrofluoric acid.

[0005] However, the above-mentioned treatment using hydrofluoric acid has a significant environmental impact, and there is also a risk of accidents where operators come into contact with hydrofluoric acid. Therefore, there is a need to remove DLC films from molds and other surfaces without using hydrofluoric acid. [Overview of the project] [Problems that the invention aims to solve]

[0006] Various aspects of the present invention aim to provide a plasma peeling apparatus and a plasma peeling method for peeling a DLC film from the surface of a mold, tool, machine part, or jig using plasma. [Means for solving the problem]

[0007] Various aspects of the present invention will be described below. [1] A plasma peeling method characterized by placing a mold, tool, machine part, or jig having a DLC film attached to its surface on the carbon-based film or carbon-based tray of a first electrode having a carbon-based film or carbon-based tray on its surface, applying plasma generation power to the first electrode in an atmosphere of oxygen gas or H2O gas to generate plasma on the surface of the mold, and using the plasma to peel the DLC film from the surface of the mold. In the plasma peeling method described above, the plasma generation power may be applied to the first electrode after connecting the second electrode, which is positioned opposite the first electrode, to earth. Alternatively, the plasma delamination method described above may be performed in a chamber connected to ground.

[0008] [2] In the above [1], A plasma peeling method characterized in that the aforementioned atmosphere is an atmosphere in which an inert gas is added to the oxygen gas or H2O gas.

[0009] [3] In the above [1] or [2], The carbon-based film or carbon-based tray is C a H b N c It consists of the following materials: A plasma peeling method characterized in that a, b, and c satisfy the following equations 1 to 3. (Formula 1) 0.25≦a≦1 (Formula 2)0≦b≦0.6 (Formula 3)0≦c≦0.6

[0010] [4] In any one of the above items [1] to [3], The plasma delamination method is characterized in that the carbon-based tray has a carbon-based film formed on the surface of the tray body.

[0011] [5] Chamber and, A first electrode disposed within the chamber, A carbon-based film or carbon-based tray disposed on the surface of the first electrode, A second electrode disposed in the chamber and disposed opposite to the first electrode, A plasma generation power source electrically connected to the first electrode, A ground electrically connected to the second electrode, An exhaust mechanism for evacuating the chamber, A gas introduction mechanism for introducing O2 gas or H2O gas into the chamber, having, The first electrode is one on which a mold, tool, machine part, or jig having a DLC film attached to its surface is placed on the carbon-based film or carbon-based tray, and is characterized by a plasma peeling device.

[0012] [6] In the above [5], The gas introduction mechanism is a mechanism for introducing the O2 gas or H2O gas and an inert gas into the chamber, and is characterized by a plasma peeling device.

[0013] [7] In the above [5] or [6], The plasma generation power source is any one of a high-frequency power source having a frequency of 10 kHz or more and 24 GHz or less, a power source for superimposing the high-frequency power source and a DC power source, a power source for applying the high-frequency power source in a pulsed manner, and a power source for superimposing the power source for applying the high-frequency power source in a pulsed manner and a DC power source, and is characterized by a plasma peeling device.

Advantages of the Invention

[0014] According to various aspects of the present invention, it is possible to provide a plasma peeling device and a plasma peeling method for peeling a DLC film from the surface of any one of a mold, tool, machine part, or jig by plasma.

Brief Description of the Drawings

[0015] [Figure 1] It is a cross-sectional view schematically showing a plasma peeling device according to one aspect of the present invention. [Figure 2]This illustrates the results of the example, and is a photograph of a sample after plasma delamination, in which a DLC film was removed from a mold sample with a DLC film deposited on its surface using plasma. [Modes for carrying out the invention]

[0016] Embodiments of the present invention will be described in detail below with reference to the drawings. However, it will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and that its form and details can be modified in various ways without departing from the spirit and scope of the present invention. Accordingly, the present invention shall not be interpreted as being limited to the descriptions of the embodiments shown below.

[0017] (First Embodiment) Figure 1 is a schematic cross-sectional view showing a plasma peeling apparatus according to one aspect of the present invention.

[0018] As shown in Figure 1, the plasma delamination apparatus has a vacuum chamber 11, which is electrically connected to earth. The vacuum chamber 11 has a lower surface portion 11, a cylindrical side portion 11b which is hermetically sealed and connected to the lower surface portion 11 by an O-ring 12, and an upper surface portion 11c which is hermetically sealed and connected to the upper part of the side portion 11b by an O-ring 13.

[0019] A plasma electrode 21, serving as the first electrode, is positioned inside the vacuum chamber 11. A carbon sheet 22 is placed on the surface of this plasma electrode 21. The plasma power supply (first electrode) 21 consists of a mold 51 on which a DLC film for surface peeling is attached is placed on the carbon sheet 22. Alternatively, the first electrode may be made from a carbon-based material. However, if the first electrode becomes worn due to repeated plasma peeling, the first electrode itself must be replaced. In this embodiment, a mold 51 with a DLC film attached is used, but it is also possible to use any tool, machine part, or jig with a DLC film attached.

[0020] In addition, in the present embodiment, although the carbon sheet 22 is disposed on the surface of the plasma electrode 21, it is also possible to dispose a carbon-based film or a carbon-based tray on the surface of the plasma electrode 21. Here, disposing a carbon-based film on the surface of the plasma electrode 21 may mean that a carbon-based film is formed on the surface or the surface and side surfaces of the plasma electrode 21, or may mean disposing a sheet-shaped carbon-based film (carbon sheet) on the surface of the plasma electrode 21. Here, the carbon-based film or the carbon-based tray is made of a material of C a H b N c and a, b, and c preferably satisfy the following formulas 1 to 3. (Formula 1) 0.25 ≤ a ≤ 1 (Formula 2) 0 ≤ b ≤ 0.6 (Formula 3) 0 ≤ c ≤ 0.6

[0021] In addition, the carbon-based tray may be one in which the above carbon-based film is formed on the surface of the tray body. The tray body may be made of a material other than the above C a H b N c material, for example, made of SUS (Steel Use Stainless).

[0022] In addition, in the present embodiment, although the carbon sheet 22 is disposed on the surface of the plasma power supply 21, the carbon sheet 22 may also be disposed on the side surface of the plasma power supply 21, or the carbon sheet 22 may have a sheet shape that covers the surface of the plasma electrode 21 (the first electrode).

[0023] The plasma electrode 21 is supported by the lower surface portion 11a, and the plasma electrode 21 and the lower surface portion 11a are insulated from each other by an insulator 3I. A plasma generation power supply 41 is electrically connected to the plasma electrode (the first electrode) 21. In addition, the plasma electrode 21 has a structure in which the inside is water-cooled (not shown).

[0024] The plasma generation power supply 41 may be one of the following: a high-frequency power supply (RF power supply) with a frequency of 10 kHz to 24 GHz, a DC power supply, a power supply that superimposes a high-frequency power supply and a DC power supply (RF superimposed DC power supply), a power supply that applies a high-frequency power supply in a pulsed manner, or a power supply that superimposes a power supply that applies a high-frequency power supply in a pulsed manner and a DC power supply. By applying a high-frequency power supply in a pulsed manner, it becomes possible to control the peeling rate (peeling time) of the DLC film and to suppress abnormal discharge.

[0025] A gas shower electrode 23 is positioned inside the vacuum chamber 11 as a second electrode, facing the plasma electrode 21. The gas shower electrode 23 is supported by an upper surface portion 11c, and the gas shower electrode 23 and the upper surface portion 11c are insulated from each other by an insulator 32. The gas shower electrode (second electrode) 23 is electrically connected to earth.

[0026] The gas shower electrode 23 is connected to a gas introduction mechanism 42 that introduces an inert gas (e.g., Ar gas) and O2 gas into the vacuum chamber 11. Specifically, the gas shower electrode 23 is configured to supply Ar gas and O2 gas in a shower-like manner toward the surface of the plasma electrode 21. In addition, N2 gas or a mixture of halogen gas and N2 gas may be used instead of halogen gas. In this embodiment, O2 gas is used, but it is also possible to use H2O gas, NO2 gas, or a mixture thereof instead of O2 gas. Furthermore, in this embodiment, Ar gas and O2 gas are supplied in a shower-like manner, but it is also possible to supply only O2 gas or only H2O gas in a shower-like manner without supplying Ar gas. If Ar gas is not supplied, the peeling rate of the DLC film will be slower, and therefore the peeling time will be longer.

[0027] Furthermore, the plasma delamination apparatus has an exhaust mechanism for evacuating the vacuum chamber 11. Specifically, the exhaust mechanism includes an exhaust path 11d provided on the side surface 11b of the vacuum chamber 11, one end of an exhaust path 11e connected to the exhaust path 11d, one side of a vacuum valve 43 connected to the other end of the exhaust path 11e, one end of an exhaust path 11f connected to the other side of the vacuum valve 43, and a vacuum pump 44 connected to the other end of the exhaust path 11f.

[0028] Next, a method for removing the DLC film attached to the surface of the mold 51 using the plasma delamination apparatus described above will be explained.

[0029] A mold 51 with a DLC film attached to its surface is placed on the carbon sheet 22 of the plasma electrode 21. Next, the vacuum valve 43 is opened and the vacuum chamber 11 is evacuated by the vacuum pump 44. As a result, the gas in the vacuum chamber 11 is exhausted through the exhaust paths 11d, 11e, vacuum valve 43, and exhaust path 11f. At the same time, the gas introduction mechanism 42 introduces Ar gas and oxygen gas (O2 gas) into the gas shower electrode 23 at a predetermined flow rate, spraying each gas in a shower-like manner towards the surface of the plasma electrode 21. The pressure is then adjusted to a predetermined level by balancing the introduction of Ar gas and oxygen gas into the vacuum chamber 11 and the exhaust of gas from the vacuum chamber 11 by the vacuum pump 44.

[0030] Subsequently, the plasma generating power supply 41 applies power to the plasma electrode 21 using one of the following: an RF power supply with a frequency of 10 kHz to 24 GHz, a DC power supply, an RF superimposed DC power supply, a power supply that applies an RF power supply in a pulsed manner, or a power supply that applies an RF power supply in a pulsed manner and a DC power supply superimposed on it. This generates plasma 61 between the plasma electrode 21 and the gas shower electrode 23, and the DLC film attached to the surface of the mold 51 is sputtered off by the Ar gas ionized by this plasma 61, while the carbon ions generated by this peeling are removed from the surface of the mold 51 as CO2 gas using ionized oxygen gas. In this way, the DLC film attached to the surface of the mold 51 is peeled off.

[0031] According to this embodiment, the surface of the plasma electrode 21 is C a H b N c A carbon sheet 22 (a carbon-based film or carbon-based tray) made of the same material is placed, and a mold 51 with a DLC film attached to its surface is placed on this carbon sheet 22. Because the carbon sheet 22 is positioned between the mold 51 with the DLC film attached to its surface and the plasma electrode 21, the carbon ions scraped off the DLC film and the surface of the carbon sheet 21 by ionized Ar gas can be converted into CO2 gas by ionized oxygen, thereby allowing the scraped carbon ions to be gasified and removed from the surfaces of the mold 51 and the carbon sheet 22. Therefore, when the DLC film attached to the surface of the mold 51 is plasma-peeled, no other substances such as films reattach to the surface of the mold 51. As a result, the surface of the mold 51 can be kept clean after the DLC film has been peeled off, and the DLC film can be cleanly peeled off from the surface of the mold 51. No oxide films or other substances reattach to the surface of the mold 51 after it has been peeled off in this way.

[0032] I will explain in more detail. If a mold 51 with a DLC film directly attached is placed on the plasma electrode 21 without placing a carbon sheet 22 on the surface of the plasma electrode 21, the carbon ions that scrape off the DLC film attached to the surface of the mold 51 with ionized Ar gas are converted into CO2 gas by ionized oxygen, and then gasified and removed from the surface of the mold 51. Furthermore, if the plasma electrode is made of, for example, Al or stainless steel, the plasma electrode is sputtered, and an Al2O3 film or Fe2O3 film, which combines with oxygen ions, adheres to the surface of the mold 51. This is the same even if only O2 gas or only H2O gas is supplied without supplying Ar gas, and an Al2O3 film or Fe2O3 film adheres to the surface of the mold 51. For this reason, in order to clean the surface of the mold 51, it is necessary to remove the Al2O3 film or Fe2O3 film attached to the mold 51 with hydrofluoric acid. In contrast, in the embodiment described above, since the carbon sheet 22 is placed on the surface of the plasma electrode 21, it is possible to suppress the sputtering of the plasma electrode 21 and the adhesion of the oxide film to the surface of the mold 51. Furthermore, as described above, since the surface of the mold 51 is covered with CO2 gas, even if a small amount of contaminant remains in the vacuum chamber 11, it is possible to prevent that contaminant from adhering to the mold 51. Therefore, the surface of the mold 51 can be kept clean after the DLC film has been peeled off, and the DLC film can be cleanly peeled off the surface of the mold 51.

[0033] Furthermore, the carbon sheet 22 is the above C a H b N c Because it is made of the same material, when the carbon sheet 22 is plasma-ground, hydrogen ions and nitrogen ions are also converted into gas. Therefore, it is possible to prevent unwanted substances from re-adhering to the mold 51 due to plasma peeling.

[0034] (Second embodiment) A plasma peeling method according to one aspect of the present invention will be described below. A mold with a DLC film attached to its surface is placed on top of a carbon-based film or carbon-based tray (e.g., carbon sheet 22 shown in Figure 1) on a first electrode (e.g., plasma electrode 21 shown in Figure 1), which has a carbon-based film or carbon-based tray (e.g., carbon sheet 22 shown in Figure 1) on its surface. Then, the mold is placed in an atmosphere of inert gas (e.g., Ar gas shown in Figure 1) and oxygen gas or H2O gas, and a second electrode (e.g., gas shower electrode 23 shown in Figure 1), which is positioned opposite the first electrode, is connected to ground. Plasma generation power is applied to the first electrode to generate plasma (e.g., plasma 61 shown in Figure 1) on the surface of the mold. This allows the DLC film to be peeled off the surface of the mold using the plasma (e.g., plasma 61 shown in Figure 1) generated between the first electrode (plasma electrode 21) and the second electrode (gas shower electrode 23). The DLC film is peeled off the surface of the mold with the inert gas (Ar gas) ionized by the plasma (e.g., plasma 61 shown in Figure 1), while the carbon ions generated by the peeling are removed from the surface of the carbon substrate as CO2 gas by ionized oxygen.

[0035] In this embodiment, a mold with a DLC film attached is used, but as in the first embodiment, it is also possible to use any tool, machine part, or jig with a DLC film attached.

[0036] Furthermore, in this embodiment, plasma is generated in an atmosphere of inert gas and oxygen gas or H2O gas in the mold, but it is also possible to generate plasma in an atmosphere of oxygen gas only or H2O gas only without supplying an inert gas. If an inert gas is not supplied, the peeling rate of the DLC film will be slower, and therefore the peeling time will be longer.

[0037] Furthermore, the carbon-based film or carbon-based tray may be made of the same material as in the first embodiment. Also, the carbon-based tray can be the same as in the first embodiment.

[0038] According to this embodiment, a carbon-based film or carbon-based tray is placed on the surface of the first electrode, a mold with a DLC film attached to its surface is placed on the carbon-based film or carbon-based tray, the second electrode is connected to earth, and plasma generation power is applied to the first electrode to generate plasma between the first electrode and the second electrode. The DLC film attached to the surface of the mold is sputtered with an inert gas ionized by this plasma. At this time, since the carbon-based film or carbon-based tray is located between the first electrode and the mold, the carbon ions scraped off the surface of the DLC film and the carbon-based film or carbon-based tray by the ionized inert gas can be converted into CO2 gas by ionized oxygen, thereby gasifying and removing the scraped carbon ions from the surface of the mold and the surface of the carbon-based film or carbon-based tray. Therefore, when the surface of the mold is plasma polished, other substances such as films do not reattach to the surface of the mold. As a result, the surface of the mold can be kept clean after the DLC film attached to the surface of the mold has been removed.

[0039] I will explain in more detail. If a mold 51 with a DLC film directly attached to the first electrode is placed on the first electrode without placing a carbon-based film or carbon-based tray on the surface of the first electrode, the same phenomenon as described in the first embodiment occurs, and the Al2O3 film or Fe2O3 film formed by sputtering the first electrode and bonding with oxygen ions adheres to the surface of the mold 51. This is also true when only oxygen gas or only H2O gas is supplied without supplying an inert gas. Therefore, in order to clean the surface of the mold, it is necessary to remove the Al2O3 film or Fe2O3 film attached to the mold with hydrofluoric acid. In contrast, in the embodiment described above, since the carbon-based film or carbon-based tray is placed on the surface of the first electrode, sputtering of the first electrode and adhesion of the oxide film to the mold surface can be suppressed. Therefore, the surface of the mold 51 can be kept clean after the DLC film is removed, and the DLC film can be cleanly removed from the surface of the mold 51.

[0040] In this embodiment, plasma is generated on the surface of the mold by applying plasma generation power to the first electrode while the mold is in an atmosphere of inert gas and oxygen gas or H2O gas, with the second electrode, which is positioned opposite the first electrode, connected to ground. However, it is also possible to generate plasma on the surface of the mold by applying plasma generation power to the first electrode while the mold is in an atmosphere of inert gas and oxygen gas or H2O gas. In this case, plasma can be generated between the first electrode and the chamber connected to ground. [Examples]

[0041] Using the plasma delamination apparatus shown in Figure 1, the DLC film attached to the surface of the mold sample was removed under the following plasma delamination conditions. • RF output of plasma generation power supply 41: 500W ·O2 flow rate: 20cc / min ·Ar flow rate: 2cc / min Oxygen pressure: 18 Pa • Polishing time: 50 minutes • Vacuum chamber 11: Stainless steel • Plasma electrode 21: Stainless steel • Gas shower electrode 23: Stainless steel • Mold sample after DLC film removal: Sample shown in Figure 2

[0042] In this embodiment, by placing a carbon sheet 22 under the mold sample and eliminating the sputtering phenomenon of the stainless steel plasma electrode 21, no oxide film remained on the surface of the mold sample after the DLC film was removed. [Explanation of Symbols]

[0043] 11… Vacuum Chamber 11a...Lower surface of the vacuum chamber 11b...Side section of the vacuum chamber 11c... Top surface of the vacuum chamber 11d, 11e, 11f... Exhaust path 12, 13…O-ring 21…Plasma electrode (first electrode) 22…Carbon sheet (carbon-based film or carbon-based tray) 23…Gas shower electrode (second electrode) 31, 32... Insulator 40... Exhaust mechanism 41…Plasma generation power supply 42...Gas introduction mechanism 43… Vacuum valve 44… Vacuum pump 51…Mold 61…Plasma

Claims

1. A mold, tool, machine part, or jig with a DLC film attached to its surface is placed on the carbon-based film or carbon-based tray of a first electrode, which has a carbon-based film or carbon-based tray on its surface. The mold, tool, machine part, or jig mentioned above is heated with oxygen gas or H2 ２ A plasma peeling method characterized by applying plasma generation power to the first electrode in an O gas atmosphere to generate plasma on the surface of the mold, and using the plasma to peel the DLC film from the surface of the mold.

2. In claim 1, In the aforementioned atmosphere, the oxygen gas or H ２ A plasma delamination method characterized by being performed in an atmosphere in which an inert gas is added to O gas.

3. In claim 1 or 2, The carbon-based film or carbon-based tray is C ａ H ｂ N ｃ It consists of the following materials: A plasma peeling method characterized in that a, b, and c satisfy the following equations 1 to 3. (Formula 1) 0.25≦a≦1 (Formula 2) 0≦b≦0.6 (Formula 3) 0≦c≦0.6

4. In claim 1 or 2, The plasma delamination method is characterized in that the carbon-based tray has a carbon-based film formed on the surface of the tray body.

5. Chamber and A first electrode disposed within the chamber, A carbon-based film or carbon-based tray placed on the surface of the aforementioned first electrode, A second electrode is placed inside the chamber and is positioned opposite the first electrode, A plasma generating power supply electrically connected to the first electrode, The ground is electrically connected to the second electrode, An exhaust mechanism for evacuating the chamber, O ２ Gas or H ２ A gas introduction mechanism for introducing O gas, It has, The plasma peeling apparatus is characterized in that the first electrode is on which a mold, tool, machine part, or jig, having a DLC film attached to its surface, is placed on the carbon-based film or carbon-based tray.

6. In claim 5, The gas introduction mechanism introduces the O ２ gas or H ２ O gas and an inert gas into the chamber, and the plasma peeling device is characterized by this.

7. In claim 5 or 6, The plasma peeling apparatus is characterized in that the plasma generating power supply is one of the following: a high-frequency power supply with a frequency of 10 kHz or more and 24 GHz or less; a power supply that superimposes the high-frequency power supply and a DC power supply; a power supply that applies the high-frequency power supply in a pulsed manner; and a power supply that superimposes the power supply that applies the high-frequency power supply in a pulsed manner and a DC power supply.

Images